Pneumatic pumping apparatus



G, B. SMALL Aug. 13, 1929.

PNEUMAT I C PUMP TNG APPARATUS Filed Oct. 28. 1927 4 Sheets-Sheet 'Il Ilill, I

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Aug. 13, 1929. G, B SMALL PNEUMATIC PUMPING APPARATUS -FI'Lledv Oct. 28,1927 4 Sheets-Sheet INVENTOR @e0/ge 5070// ATTORNEY Aug. 13, 1929. G. B.SMALL PNEUMATIC PUMPING APPARATUS 4 Sheets-Sheet 4 Filed Oct. 28, 1927 m.NNN

mvENToR @e0/565. 5070// BY ATTORNEY Paten-ted Aug. 13,1929. i i1,724,854 UNITED STATES PATENT OFFICE.

GEORGE B. SMALL, OF TULSA, OKLAHOMA, ASSIGNOR OF THREE-FOURTHS T TIDALOIL COMPANY, 0F TULSA, OKLAHOMA, A CORPORATION OKLAHOMA.

PNEUMATIC PUMPING APPARATUS.

Application med october 2s, 1927. serieu 110. 229,414.

My invention relates to pneumatic pumpto the housing section by capscrews 16,17 ing apparatus, and more particularly to apand 18 asshown.paratus of that character for use in connec- Within the lower housingsection 11 is a. tion with oil wells of such limitedyield as valvechamber 19, having a seat 20 and port to require only occasionalpumping, the 21, the seat and port formed in a diaphragm 60 principalobject of the invention being to 22 having an upwardly facing seat 23for eliminate necessity for mechanical operation the valve head 24 of apiston 25 mounted in and personal supervision in recovery of the apiston chamber 26 which communicates oil by supplying fluid pressuremedium to with the upper portion of the valve chamber l the Well fordisplacing the accumulated oil 19 through the port 21. The piston 25 is65 at intervals determined by rapidity of the provided with an annulargroove 27 for yield; the present application being a confacilitatingbleeding of the major flow of tinuation in part of my application filedpressure medium through a port 28 in said May 23, 1927, Serial No.193,417. housing, as will presently be described.

In accomplishing this and other objects of Connected with the piston 25by a rod 29 70 my invention I have provided improved deand locatedwithin the lower portion of the tails of structure, the preferred formsof valve chamber 19 is a valve 30 adapted to which are illustrated inthe accompanying rest on the seat to close the port 21 and drawings,wherein: having a guide collar 31 operable in the 20 Fig. 1 is a sideelevation of apparatus emport 21 when the valve is moving to and 75bodying my invention, illustrated in connecfrom its seat. The valve isnormally yieldtion with an oil Well, the valve mechanism ingly urged toits seat by a spring 32 which and Well being in central section, withthe rests on the cap plate 15 and bears against valve closed to shut offmajor flow of fluid the bottom of the valve 30 about a. guide pressuremedium and permit accumulation pin 33 on the lower face of the valve. 80of liquid in the Well. The piston 25 and valve 30 are cylindri- Fig. 2is a similar view of the same parts, cal and of differential diameter,the face of showing the valve open to permit major flow the pistonhaving a greater surface area than of pressure medium for displacingliquid that of the valve and also greater than 30 from the well. that ofthe valve head 24 on its inner end, B5

Fig. 3 is a similar vi'ew of the same parts for a purpose presentlydescribed. The vpisin position for shutting off the major flow ton 25 isillustrated conventionally but may of pressure medium. be of a type toretain a suliieient amount of Fig. 4 is an enlarged central verticalsecair in the chamber 26 to resist closing of the 35 tion of the majorflow control valve. valve 30 during the major flow period. 90

Fig. 5 is a similar View of the low equal- Leading to the lower portionof the valve izer valve. chamber 19 through the late 15 is a pipe 34Fig. 6 is a similar view of the minor flow for supplying a major flldwof pressure mebleeding valve. dium to the valve chamber from a compres-Referring more in detail to the drawings: sor or other source of supplindicated by 95 1 designates a Well hole terminating in a portion of acylinder C. pening to the the usual shot hole 2, and 3 a well casingport 21 is a lateral port 35 terminating in comprising a shoe 4 seatedon cap rock 5 a socket 36, and threaded into said socket is above theloil sand 6, in accordance with coma conduit 37 leading to the casinghead and mon practice. The casing 3 is capped by a opening therethroughfor delivery of a. ma- 100 head 7 to seal the easing and retain theartijor flow of fluid pressure medium into the ticial fluid pressure-medium therein. Extop of the well casing. An orifice plate, intendingthroughthe head 7 is tubing 8, terdicated bv the fianges 38, isinterposed in minat-ing at its lower end in the shot hole the line 37for producin a differential pres 5o in a perforated section 9 andleading from sure on opposite sides o? the equalizer valve 105 Jthe topof the Well to a suitable storage rehereinafter described. ceptacle orpipe line (not shown). Opening from the lower portion of the 10designates a valve housing, preferably valve chamber 19 is a b -passchannel 39, formed in three sections 11, 12 and 13, with terminating ina valve c amber 40, having top and bottom cap plates 14 and 15, attachedthe seat 41 and a bore 42 leading to an upx10 per-piston chamber 43, andcommunicating through a bore 44 with the piston chamber 26 so that whenthe by-pass is open,.flu1d pressure medium may pass from the prlmaryvalve chamber 19 about the valve 30 into the. top ot the 'piston chamberto actuate the piston and unseat the valve against the tension of itsspring 32 and the force of the pressure medium delivered through pipe34.

Located Within the valve chamber 40 is a Valve45 having a rod 46extending through the bore 42 into the piston chamber 43. Mounted on therod 46 within the chamber 43 isa piston 47, and-seating on the bottom ofthe chamber 43 and bearing against said piston is a spring 48 whichnormally yieldingly retains the piston 47 at the upper lm ut of itsmovement to seat the valve 45 and prevent fiow of pressure medium from'the primary valve chamber to the piston chamber 2,6.

Leading from the supply lineI 34 around the housing to a port 49open-ing tothe piston chamber 43 above the piston 47, is a bypass pipe50, valved at 51 torestrict fionv of `pressure medium from the majorsupply to thepiston chamber 43. Leading from the -upper portion of thepiston chamber 43 is a line 52 which extends through the casing head 7and through the casing to near the bottom of the well, Where it hasunrestricted outlet. The line 52 is provided with a backycheck valve 53to prevent outlet of pressure medium from the well through this line,and is also provided with a bleeding valve operable as presentlydescribed, for effecting a quick return of valve 45 to its seatimmediately upon opening of the major flow ot pressure medium to theWell.

Opening from the lou'er portion of the piston chamber 43 is a port 54,and threaded into said vport is a line 55 leading-through a four-Wayunion 56 to a line 57 opening through' the casing head 7 and terminatingin an open end within the upper portion of the Well casing.

lVith the parts heretofore described, a minor loiv ot' pressure mediumis conducted from the snpplypipe 34 around the valve housing to theupper portion of the piston chamber 43, through said chamber into the.tine 52, through the check valve 53 and the bieeding valve chamber andon through the line 52 t-o near the bottom of the Well, the minor flowescaping into the Well being relieved through the line 37, throat 2l andvent 28 to atmosphere. Under these conditions the valve 45 is heldclosed by the spring 48 and there is no major ilotv of pressure mediumto the Well through line 37, the valve 3G being seated b v the spring 32and by torce oi' pressure medium delivered through the line 34.

Located adjacent the primary piston chamber 26 and communicatingtherewith ,ing valve seat 95.

.67, surrounding the rod 64, seating on the .floor of the piston chamberand bearing against t-he under face of the piston. Opening from thelower portion of the piston chamber 65 is a port 68 and threaded intosaid port and leading to the four-Way union 56 .is a line 69, throughwhich pressure medium released romthe ive'll through thel line 57 isdelivered to the bottom of the piston chamber 65 to balance pressure inthe upper portion ofthe chamber under the conditions presentlydescribed.

Located adjacent the housing 10 is a valve housing 7 O comprising thevalve and piston chambers 71 and 72, closed by the sealing caps 7 3 and74, the valve chamber 71 havingV a seatf 75 and port 76, theportcommumcat-l ino' Witha' channel 77 Within the housing 7 0,

lhreaded into -the channel `77 is a line 78, leading to a, channel 79 inthe housing 10 through which the line communicates with the upperportion of the piston cham'- ber 65. Leading from the line 37 at thehigh pressure side of the orifice plate 38 is a line 80, opening to achannel 8l in the valve housing 7 0 which communicates with the valvechamber 71. Located Within the chamber 71 is a valve 82'yieldingly heldto the seat 75 by a spring 83 that seatson the plate 73 forming part ofthe valve housing. The valve 82 has a stem 84 extending 'through thevalve housing into the piston chamber 72 Where it carries a piston 85 ofgreater surface area than the valve82 so that when equal pressure isappliedto the piston and the valve, the valve will be unseated. Openingthrough the cap 74 to the .piston chamber 72 is a line 86 leading to thefour-way union'56, yand whereby pressure medium released from the Wellis delivered through line 86 to the piston chamber 72. v-

The bleeding valve. in the minor flow line includes a. housing 87 havingchambers 88 and 89 at its upper ami lower ends sealed bv plates 90 and91 and separated by a f diap ragm 92. Cent-rally lo ated 'within thediaphragm is a port and leading from said port through .the diaphragm tothe eX- terior of the housing is an open channel 94. Surrounding theport .im upwardly tac- I Ext ning through the part of' the diaphragm bconcentric l1-ith the p n '93, is an opening 96, ann ble'in )ening 96 isa i *v combination i sion. .fon valve stem 94.

Located Within the chanahcr 89 in the lovver viv he channel 94,

end of the housing and xed on the lower end of the rod 97 is a piston 98adapted for reciprocation in the chamber 89. Located within the chamber88 in the upper end of the housing and iiXed on the upper end of the rod97 is a valve 99 adapted for reciprocation in the chamber 88 to open andclose the port 93. The housing 87 is interposed in the line 52, thespaced ends of the line being threaded into openings 100 and 101 atopposite sides of the housing and communicating with the chamber 88, sothat when the valve 99 is closed (Figs. 1 and 3) Huid pressure medium mapass through the chamber 88 during its ow through the line 52.

102 designates a branch leading from the major flow line 37 at a pointbetween the main housing 10 and orifice Valve 38 and threaded into anopening y103 in bottom plate 91 of the bleeding valve housing 87 fordelivery of pressure medium from the major flow line into the chamber 89below the piston 98.

The rod 97 is of a length to provide movement of the piston 98 and valve99 in their respective chambers and the parts are of sufficient weightto seat the valve by gravity when the piston is unrestrained by-pressuremedium in thechamber 89.

With the parts constructed and assembled as described, the apparatus maybe operated as follows:

Assuming that the liquid in the well is at a low level, as illustratedin Fig. 1, major flow of pressure medium is shut ofi' at the primaryvalve 30, a minor flow of'the pressure medium passing from the supplyline 34 to the upper portion of the piston chamber 43 and thence throughthe lme 52 to the lower portion of the well, the valve 99 bein closed bminor ow of pressure medium is released from the well through the majoriow line 37, port 21 and vent 28 to atmosphere, so that the spring 48,assisted b pressure of air in chamber 40 against va ve 45 retains thepiston 47 iat the upper limit of its movement and the valve 45,controlling the bypass 39, on its seat, preventing escape of fluidmedium Ifrom the valve chamber 19 into the piston chamber 26.

The parts remain inthe balanced condition above described while liquidis accumulating in the bottom of the well to a level which will submergethe lower end of the line 52 and liquid seal the line. When thissubmergence occurs, pressure medium Howing through the by-pass pipe 50accumulates in the upper portion of the piston chamber 43 until itovercomes pressure on the valve 45 and the te'nsionof the spring 48. Thepiston 47 is then forced downwardly in the chamber 43, forcing the valve45 from its seat and opening the by-pass 39 to the primary pistonchamber. Pressure in the line 50-52 is relatively low (about threepounds) because of the restriction in line 50, and pressure in thechamber 40 rela-tively high (one hundred fifty pounds orV over) becauseof direct connection between the chamber and major flow line, but thevalve 45 is opened against high pressure because of the differentialareas of the piston 47 and valve '45. Flow of pressure pass onto thepiston of the primary lowers the piston and unseats valve due todifferential areas and piston. A major flow of pressure medium thenpasses through the line 37, and orifice plate 38 and through the casinghead into the top of the well in sufficient volume to displace li uid inthe well and force it out through t e tubing 8. Until the major valve,the primary iiow line'has been opened by unseating of` valve 30,pressure in valve 99 closed.

During the displacement of the liquid by the major flow and while theminor iow line is sealed, some of the major How will be released fromthe well through the line 57 into the piston chambers and 72 as well asinto chamber 43. This How of Huid pressure medium only serves, however,to supplement action of the spring 67 in retaining the piston 66 at theupper limit of its travel, and the valve 63 closed, and pressure fromthe flow into the piston chamber 72 is resisted by pressure of the Howthrough line from the line 37 at the high pressure side of the orificeplate 38, until the return ressure builds up in chamber 72 suicientiy toopen the valve 82 against pressure from the major flow and tension ofthe spring 83 because of differential area of the plston 85 the line 52retains the ,g and valve-82. pressure in the chamber 88. This nImmediately .upon opening of the' valve 30 pressure medium is passedfrom the hifrh pressure side of the orifice valve 38 int e major line 37to the chamber 89 in `the housing 87 lifting the valve 99 against therelatively low pressure in line 52 and relieving the line 52,unbalancing the piston 47 so that the piston is lifted by force of thepressure medium against the valve 45 supplemented by liftin force of thespring 48 and by ressure of t e medium passed from the wel through line57, union 56 and line 55 to the lower portion of chamber 43. The valve45 is thereby closed, shutting olf supply of pressure medium to themajor piston chamber 26 through the by-p'ass 39. The major piston is,however, retained in open position and the valve 30 unseated by pressuremedium trapped in the chamber 26, and pressure medium continues to fiowinto the well through line 37 for vdisplacing the well Huid.

Durin the displacement operation pressure me ium supplied to the well inmajor medium through the byof the valve flow escapes through the line57, the fourway union 56'and pipe 86 into chamber 72v and unseats thevalve 82 because ofthe diferential in area between the piston 85 and thevalve 82, and pressure medium from the l line 80 passes through the line78 to the topv -of the chamber 65.

While the. pressure in the top of chamber 65 is greater than thatbelowthe piston 66, it is not sufficient' to overcome tension of thespring 67 and the valve 63 remains closed. When the fluid has beendisplaced from the Well, the displacing pressure medium escapes from thewell through tubing 8, releasing pressure in the line57 so that it dropsbelou7 that in the `line 37 backv of the orifice valve 38, and thelhigher pressure in theline 37,y 80 and 78 returns to its'seat, therebyconditioning the apparatus for a succeeding operation.

While filling of the Well to a level for submerging the minor flow linemay require considerable time, dependent on volume of yield of the Well,discharge under pressure ot the major flow of pressure-medium isrelatively quite rapid; consequently the normal condition of theapparatus is that wherein said piston,

the major the major valve 30 is closed.

It is apparent therefore that I have provided an apparatus for pumpingWellspneumatically which is automatic in its operation in response tovariation of level of yliquid in the Well, so that the displacing fluidmedium is admittedto the Well only when there is a sullicientaccumulation of fluid in the Well and that such control is y'effectedWithout Working parts in the Welland irrespective of the time requiredfor accumulation of the fluid. What I claim and desire to secure bylTietters Patent is :v

1. Pneumatic pumping apparatus including in combination with a Wellhaving a discharge line and a source of .supply of liiid pressuremedium, a major {iow line leading from the source of pressure mediumsupplyto the well, means including a valve and an operating pistoncontrolling flow through iow line, a minor flow line leading from theVsource of pressure medium supplyl to the Well having interrupted flow atone side of said piston, a return line leading vfrom -the Well to theother side of pressures in the major-flow and return lines for relievingthe piston, a valve housing including a valve chamber interposed in theminor llow line and having an outlet to atvsupply of -sure ot' fluidmeans responsive to change in mospliere, and containing a pistonchamber, a valve in the'valve chamber, a piston in the p1ston chamberconnected with the valve, and a branch on the major How line leading tosaid piston chamber to provide control of the last-named valvebyvariation in pressure in the `major and minor flow lines.

2. Pneumatic pumping apparatus comprising in combination with a Wellhaving a discharge line and a source' of supply of fluid pressuremedium, a primary conduit for supplying a mainv volume of fluid `mediumto the Well, a secondary conduit for constantly supplying a limitedvolume of fluid medium to the Well and arranged to be sealed by liquidrising in the Well, a valve controlling iioW through the primaryconduit, a valve mechanism controlling operation of said valve, andmeans for returning fluid medium from the Well for cooperation withfluid medium in the secondary conduit for normally balancing said valvemechanism, the valve mechanism being operable to effect opening of saidvalve by excessive pressure in the secondary conduit induced bysubmergence of the secondary conduit in liquid rising in the Well, andmeans for effecting closure of the valve.

3. Pneumatic pumping apparatus comprising in combination With a Wellhaving a discharge line and a source of supply of 'a valve in saidchamber normallyvelosing said conduit, a piston-operatively connectedlwith the valve, separate valves controlling fluid pressure `medium tothe piston and relief ot' fluid pressure medium from,the\ piston. asecondary conduit for conducting limited supply of fluid pressure mediumto the well and arranged for submergence by liquid rising'in the Welland including a piston chainber, a piston in said chamber connected withsaid supply valve, means for returning fluid pressure medium from 'theWell to said piston chamber to normally balance'the supply valve piston,means urging the supply valve to closed position and yieldableunderprespressure medium trapped in said chamber by liquid rising inthe well,and means controlled by -variation in pressure in thewell controllingthe relief valve.

4. Pneumatic pumping apparatus comprising in combination with a wellhaving a` discharge line and a' source of supply o f fluid pressuremedium, a primary conduit for conducting Huid pressure medium. to thevivell,inclu ling a valve housing containing valve and piston chambersand ahy-pass between said chambers including a valve chamber, a valve inthe primary valve chamber and a piston in nected with said valve,yielding means northe piston chamber conmally seating the valve to stopflow through the conduit, a secondary conduit for supplying fluidpressure medium to the wel including a piston chamber, a valve in thebypass chamber, a piston in the secondary conduit chamber operativelyconnected with the by-pass valve, means for returning fluid pressuremedium from the well to the secondary conduit chamber to normallybalance said piston, yielding means normally urging the by-pass valve toclose the bypass. and yieldable under excessive pressure induced in thesecondary conduit by sealing of said conduit by liquid rising in thewell to admit fluid pressure medium to the primary valve piston chamber,and valve mechanism controlled by variation in pressure in the well forrelieving the primary valve piston to permit said valve to close. p

5. In pneumatic pumping apparatus, a valve mechanism comprismg incombination with a well having a discharge line and a source of supplyof fluid pressure medium connected primary valve and piston chambers, aby-pass connectin said chambers and including a valve cham er, an outletport'l for the piston chamber including a valve chamber and by-pass andrelief piston chambers, a valve in the primary valve chamber, a pistonin the primary piston chamber connected with said valve, means normallyyieldingly seating the valve, a primary conduit having sectionscommunicating with the H primary valve chamber at opposite sides of saidvalve for supplying fluld pressure medium to the well, pistons in saidby-pass and relief piston chamber, valves in said by-pass and reliefvalve chambers connected with corresponding pistons, means normallyyieldingly seating said valves, a secondary Conduit for by-passing fluidpressure medium from the supply section of the primary conduit throughthe outer end of the by-pass piston chamber to the well and arranged forsubmergence by liquid rising in the well, means connecting the wellsection of the primary conduit with the outer end of the outlet ortpiston chamber, a piston valve controlling flow through said connectingmeans, and means for returning fluid pressure medium from the well tothe opposite ends of the by-pass and outlet port piston valve chambersto normally balance the pistons, and to operate relation with saidconnecting valve piston to shift said connecting valve.

6. In combination with a well having a discharge line, a source of suppl.of fluid pressure medium, aconduit lea ing from said source of supplyto the well, a valve normally closing said conduit, a secondary conduitleading to the well, a line for supplying pressure medium for openingthe valve,a valve in said line responsive t0 rise in pressure in thesecondary conduit to open the line, and a valve in said secondaryconduit responsive to pressure in the supply conduit for relieving thesecondary con uit to permit the line valve to close, and means forenabling closure of the conduit valve.

7 In combination With a well having a discharge linevand a source ofsupply of fluid ressure medium, major and minor flow lm es connectedwith said source of supply and having separate open communication withthe well, with the outlet of the minor flow line belowl that of themajor flow line, means normall restraining flow through theJ major flow11ne, and means responsive to variation in pressure vin the minor flowline controlling said restrainlng means. g

8. In combination discharge line and. a source of fluid pressure medium,flow lines connected with ply and having tion with the Well, with theoutlet of the minor flow line below that of the major flow line, meansnormally restraining flow through the major flow line, and meansresponsive to rise in pressure in the minor flow line induced by sealingof said minor flow line by liquid in the well controlling saidrestraining means.

9. In combination with a Well having a discharge line and a source ofsupply of uid pressure medium, primary piston and valve chambers, a highpressure line leading from the source of supply through the primaryvalve chamber to the well, connected primary piston and valve membersrespectively located in said leading from the hi h primary piston chamsupply of major and minor said source of suppressure line to the er, alow pressure line leading from said source of supply to the well,connected secondary lpiston and valve members having chambers interposedin the low pressure line and by-pass respectively, responsive tovariation in pressure in the low pressure line for controllin flowthrough said by-pass, a return line or conducting pressure medium fromthe well to the secondary iston chamber for balancing pressure on t esecondary piston, means yieldingly urging the secondary piston to closethe secondary valve, and means for enabling closure of the rima valve.

10. In combination Wit a we having a discharge line and a source ofsupply of fluid pressure medium, a hi h pressure-line leading from thesource of supply to the well, connected primary piston and valve membersfor controlling flow through the high pressure line, the piston membermovable in a chamber rovided with inlet and vent ports, meansorsupplying high pressure medium to said chamber through the inlet port,a low pressure line leading from the source of supply to the well, avalve with a well having a' separate open communicachambers, a by-passfor said inlet port responsive to difference in pressure vin the highand low pressure lines, a return line from the well, and a valveresponsive to diierence in pressures in the high pressure and returnlines controlling said vent port.

11. In combination with a Well having a discharge line and a source ofsupply of fluid pressure medium, a hi h pressure line leading from thesource o supply to the Well, connected primary piston and valve membersfor controlling How through the high pressure line, the piston membermovable in a chamber provided With inlet and vent ports, means forvsupplying high pressure medium to said chamber through the inlet port, alow pressure line leading from the source of supply to the Well, 'avalve for said inlet port responsive to difference in pressures in thehigh and low pressure lines, a return line from the Well, and a valveresponsive to differential in pressures in the return and high pressurelines controlling said vent port. y

12. In combination with a Well having a discharge line and a source ofsupply of iiuid pressure medium, a hi h pressure line leading from thesource o supply to the Well, means including a primary piston valve andpiston and valve chambers controlling i'low through the high pressureline, a bypass for conducting high pressure medium to the pistonchamber,a low pressure line leading from the source of supply to the well, valvemechanism responsive to difference in pressures in the high and lovvpressure lines controlling loW through the bypass, a vent for theprimary piston chamber, means including a piston valve and piston andvalve chambers controlling said vent, a return linefrom the Well openingto the vent piston chamber below the piston to .normally retain the ventvalve closed, a

branch leading from the high pressure line to the opposite side of thevent piston chamber, and differential area valve mechanism responsive todifference in pressures in the high pressure and return linescontrolling disposition of pressure medium in the vent piston chamber.

i3. In combination with a Well having a discharge line and a source ofsupply of fluid pressure medium, a high pressure line lead-` ing fromthe source of supply,to the Well, means including a primary piston valveand piston and valve chambers controlling i'loW through the highpressure line, a by-pass for conducting high pressure medium to thepiston chamber, a low pressure 'line leading from the source of supplyto the Well, valve mechanism responsive to difference in pressures inthe high and lovv pressure lines controlling floW through the by-pass, avent for the primary piston chamber, means includdischarge line andasource of supply of Huid 1 pressure medium, a high pressure line leadingfrom the source of supply to the Well, means including a primary pistonvalve and piston and valve chambers controlling flow through the highpressure line, a by-pass for conducting high pressure medium to thepiston chamber, a low pressure line leading from the source of supply tothe Well, valve mechanism responsive to dierence in pressures in thehigh and low pressure lines controlling ioW through the by-pass, a ventforthe primary piston chamber, means including a piston valve and pistonand valve chambers controlling said vent, a return line from the wellopening to `the vent piston chamber below the piston to normally retainthe vent valve closed, a branch leading from the high pressure line tothe opposite side of the vent piston chamber, and valve 'mechanismresponsive to accumulation of pressure in the return line for shiftingthe valve mechanism to open the branch line and eilect opening of thevent in response to drop in pressure in the return line resulting fromrelief of pressure in the Well through said discharge line.

15. In combination with a Well having a discharge line, a source ofsupply of fluid pressure medium having a major iloW line leading to theWell, pressure reducing means in said line, valve mechanism controllingiow at the high pressure side of said line, a minor flow line leadingJfrom said source of supply to the Well, a line for conducting ressuremedium from said source of'supp y to open said valve mechanism, meansresponsive to variation in pressure in the minor flow line controllingflow through the conducting line, and means for enabling closure of saidvalve mechanism. v

16. In combination with a Well having a discharge line, a source ofsupply of iuid pressure medium having a major low line leading to thewell, pressure reducing means in said line', valve mechanism controllingflow at the high pressure side of said line, a minor fiow line leadingfrom said source of supplyto the Well, a line for conducting pressuremedium from said source of supply to open said valve mechanism, meansresponsive pressure side of the major fioW line for bleeding the minorflow line, and means for enabling closure of the valve.

17. In combination with a Well having a discharge line, a source ofsupply of fluid pressure medium having a major flow line leading to theWell, pressure reducing means in said line, main valve mechanismcontrolling flow at the high pressure side of said line, a minor flowline leading from said source of supply to the Well, a line forconductingpressure medium from said source of supply to open said valvemechanism, means responsive to variation in pressure in the minor flowline controlling flow through the conducting line, a vent for the minorflow line, a piston valve normally closing said vent, and a. line forconducting pressure medium from the high pressure side of the major fioWline to open said piston valve to permit the main valve mechanism toclose.

18. In combination With-a Well having a discharge line, a source ofsupply of fluid pressure medium having a major flow line leading to thewell, pressure reducing means in said line, valve mechanism controllingflow at the high pressure side of said line, a minor flow line leadingfrom said source of supply to the Well, a line for conducting pressuremedium from said source of supply to open said valve mechanism, meansresponsive to variation in pressure in the minor flow line controllingiioW through the conducting line, and means responsive to difference inpressure in the high and low sides lof the major flow line controllingrelease of pressure on said valve mechanism to permit said valvemechanism to close.

19. In combination with a well having a discharge line, a' source ofsupply of fluid ypressure medium having a major flow linel leading tothe well, pressure reducing means in said line, valve mechanismcontrolling flow at the high pressure side of' said line, a minor fiowline leading from said source of supply to the Well, a line forconducting pressure medium from said source of supply to open said valvemechanism, means responsive to variation in pressure in the minor flowline controlling fioW through the conducting line, valve mechanismcontrolling relief of pressure onf the major line valve mechanism, aline leading from the Well to one side of the relief valve mechanism, abranch line leading from the high .pressure side of the major flow lineto the opposite side of the relief valve mechanism, and valve mechanismin said branch line responsive to rise in pressure in the Well to opensaid line and admit pressure medium therefrom to the relief valvemechanism to effect'closure of the primary valve mechanism.

20. In combination Witha Well -having a discharge line, a source ofsupply of fluid pressure medium having a major flow line leading to theWell, pressure reducing means in said line, valve mechanism controllingflow through the high pressure side of said line,a minor fioiv lineleading from said source 'of supply to the Well, a line for conductingpressure medium from said source of supply to said valve mechanism,means responsive to variation in pressure in the minor flow linecontrolling flow through the conducting line, valve mechanismcontrolling relief of pressure on the major line valve mechanism,including a piston, a branch line leading from the high pressure side ofthe major flow line to the valve opening side of said piston, a returnline leading from the Well to the valve closing side of said piston, anda differential area piston valve controlling said branchzline,responsive to rise in pressure in the wellto open the branch line. l

21. In combination with a well having a discharge line and a source'ofsupply of fluid pressure medium, differential 'pressure major and minorfiow lines leading from said source of supply to the Well, and meansresponsive to change in differential of effective forces in the majorand minor flow lines, induced by liquid sealing `of the minor flow line,controlling flow throughI the major flow line, and a relief valve in'said minor flow line operable in response to change inpressures in saidlines.

22. In combination with a Well having a discharge line and means forsupplying a fluid medium under substantially constant pressure, majorand minor fioW lines connecting said sourcelof supply with the well,

a return line leading from the Well, means y responsive to change indifferential of effective forces inthe minor flow and return lines andthe major flow line, induced by liquid sealing of the minor flow linecontrolling flovv through the major flow line.

23. In combination discharge line and a fluid pressure medium, major andminor flow lines leading from said source of supply to the well, meansincluding a piston valve having separate piston and valve chambers,controlling How throu h the major flow line, a line leading fromv said.source of supply to the piston chamber, secondary valve mechanism'responsive to change in differential of effective forces in the majorand minor flow lines cont-rolling flow through the line tothe pistonchamber, a return line leading from the Well, a vent line leading fromthe piston chamber, and valve mechanism responsive to changes inpressure in the major flow and return lines controlling flow through thevent line.

24. In combination with a well having a discharge line and asource ofsupply of fluid pressure medium, differential pressure major and minorflow lines leading from said source of supply of differential pressurewith a Well having av flow through the line to the piston c'hamber,

source of supply to the Well, means including a piston valve havingseparate piston and valve chambers, controlling iow through the majorflow line, a line leading from said source of supply to the pistonchamber, secondary valve mechanism responsive to change indiferential ofeffectiveforces in the major and minor flow lines controlling a returnline leading from the Well, a vent 10 and responsive to pressuresupplied from the major flow line when the major flow line is open toopen the vent line.

In testimony whereof I affix my signature.

GEORGE B. SMALL.

